The present invention generally relates to print media products for receiving printed images thereon. More particularly, the invention described herein involves image-receiving sheet materials incorporating a specialized arrangement of layers and components which cooperate to produce a number of important benefits in a simultaneous fashion including but not limited to a high degree of lightfastness, gloss-control, rapid drying time, and others as discussed below.
Substantial developments have been made in the field of electronic printing technology. A wide variety of highly-efficient printing systems currently exist which are capable of dispensing ink in a rapid and accurate manner. Thermal inkjet systems are especially important in this regard. Printing units using thermal inkjet technology basically involve an apparatus which includes at least one ink reservoir chamber in fluid communication with a substrate (preferably made of silicon [Si] and/or other comparable materials) having a plurality of thin-film heating resistors thereon. The substrate and resistors are maintained within a structure that is conventionally characterized as a xe2x80x9cprintheadxe2x80x9d. Selective activation of the resistors causes thermal excitation of the ink materials stored inside the reservoir chamber and expulsion thereof from the printhead. Representative thermal inkjet systems are discussed in, for example, U.S. Pat. No. 4,771,295 to Baker et al. and U.S. Pat. No. 5,278,584 to Keefe et al. which are both incorporated herein by reference.
The ink delivery systems described above (and comparable printing units using thermal inkjet technology) typically include an ink containment unit (e.g. a housing, vessel, or tank) having a self-contained supply of ink therein in order to form an ink cartridge. In a standard ink cartridge, the ink containment unit is directly attached to the remaining components of the cartridge to produce an integral and unitary structure wherein the ink supply is considered to be xe2x80x9con-boardxe2x80x9d as shown in, for example, U.S. Pat. No. 4,771,295 to Baker et al. However, in other cases, the ink containment unit will be provided at a remote location within the printer, with the ink containment unit being operatively connected to and in fluid communication with the printhead using one or more ink transfer conduits. These particular systems are conventionally known as xe2x80x9coff-axisxe2x80x9d printing units. A representative, non-limiting off-axis ink delivery system is discussed in, for example, U.S. Pat. No. 5,975,686 to Hauck et al. which is also incorporated herein by reference. The present invention as described below (which involves a plurality of novel ink-receiving print media products) is applicable to both on-board and off-axis systems (as well as any other types which include at least one ink containment vessel that is either directly or remotely in fluid communication with a printhead containing one or more ink-ejecting resistors therein). Furthermore, while the print media materials outlined herein will be discussed with primary reference to thermal inkjet technology, it shall be understood that they may be employed in connection with other ink delivery systems and methods including but not limited to piezoelectric drop devices of the variety disclosed in U.S. Pat. No. 4,329,698 to Smith and dot matrix units of the type described in U.S. Pat. No. 4,749,291 to Kobayashi et al., as well as other comparable and diverse systems designed to deliver ink using one or more ink delivery components/assemblies. In this regard, the claimed print media products and methods shall not be considered xe2x80x9cprint method-specificxe2x80x9d.
In order to effectively generate printed images using the various ink transfer techniques and systems discussed herein (again, with primary but not exclusive reference to thermal inkjet technology), ink-receiving print media materials must be employed which are capable of efficiently accomplishing this goal. Ideally, to achieve maximum efficiency, print media materials should be able to provide numerous advantages and benefits including but not limited to (1) a high level of light-fastness, with the term xe2x80x9clight-fastnessxe2x80x9d being generally defined herein to involve the capacity of a print media product to retain images thereon in a stable fashion without substantial fading, blurring, distortion, and the like over time in the presence of natural or made-made light; (2) rapid drying times in order to avoid smudging and image deterioration immediately after printing is completed due to contact with physical objects and the like; (3) the fast and complete absorption of ink materials in a manner which avoids image distortion caused by color bleed (e.g. the undesired migration of multi-colored ink components into each other) and related difficulties; (4) a highly water-fast character (with the term xe2x80x9cwater-fastxe2x80x9d being generally defined to involve the ability of a print media product to produce a stable image with little or no fading, run-off, distortion, and the like when the image is placed in contact with moisture); (5) the generation of xe2x80x9ccrispxe2x80x9d images with a distinct and defined character; (6) low material costs which enable the print media products of interest to be employed for mass market home and business use; (7) excellent levels of image stability and retention over long time periods; (8) minimal complexity from a production and material-content standpoint which leads to reduced fabrication costs and greater product reliability; and (9) a high level of gloss-control which is achievable in a rapid and effective manner during production through only minor adjustments in the manufacturing process. The term xe2x80x9cgloss-controlxe2x80x9d is generally defined herein to involve the ability, during fabrication, to generate a print media product having high-gloss levels for the generation of photographic quality images if desired, a semi-gloss character if needed, or other gloss parameters. In particular, the manufacturing process should be highly controllable in order to achieve a variety of different gloss characteristics without requiring major adjustments in processing steps and materials.
In the past, many different print media sheets using a wide variety of different ingredients, production techniques, layering arrangements, and the like have been fabricated for a multitude of specific purposes. For example, as generally discussed in the representative patent documents listed below, the following items have been investigated and/or employed in the production of print media products to achieve a broad spectrum of goals: modifications in the types of materials being used, the amounts of such materials, the relative particle sizes thereof, the particular layering arrangements being chosen, and the adjustment of various factors including pore size, pore volume, layer thickness, particle orientation, surface roughness, surface rigidity, air permeability, and other similar parameters. Representative patents (incorporated herein by reference) which discuss at least one or more of the above-listed factors (and others) are as follows: U.S. Pat. Nos. 4,391,850; 4,440,827; 4,446,174; 4,474,847; 4,567,096; 4,623,557; 4,642,247; 4,780,356; 4,785,313; 4,879,166; 5,008,231; 5,013,603; 5,091,359; 5,104,730; 5,194,347; 5,266,383; 5,354,634; 5,397,619; 5,463,178; 5,472,773; 5,514,636; 5,576,088; 5,605,750; 5,609,964; 5,635,297; 5,691,046; 5,723,211; 5,753,588; 5,755,929; 5,804,293; 5,863,648; 5,882,388; 5,912,071; 5,928,789; 5,962,124; 5,965,244; 5,977,019; 5,985,076; and 6,063,489.
Notwithstanding the various media products discussed in the above-listed patents and prior activities in this field, a need remains for print media materials (namely, ink-receiving sheets) which are able to capture and retain clear, distinct, and accurate images thereon that are likewise characterized by a number of specific benefits in combination. These benefits include but are not limited to items [1]-[9] recited above both on an individual and simultaneous basis in a substantially automatic manner (with the simultaneous achievement of such goals being of particular importance and novelty). The attainment of these objectives is especially important regarding the following specific items: gloss-control (with high-gloss levels being of primary interest in a preferred embodiment), excellent light-fastness, rapid drying time, and the generation of clear, durable, and distinct printed images. The present invention and its various embodiments perform all of the functions recited above in a highly effective and simultaneous manner while using a minimal number of material layers, chemical compositions, and production steps. In particular (as will become readily apparent from the discussion provided herein), the foregoing advantages and attributes are achieved through a highly unique and specialized layering arrangement and selection of materials. As a result, print media structures of minimal complexity are created that nonetheless exhibit a substantial number of beneficial characteristics and features in an unexpectedly efficient fashion. In this regard, the present invention represents a distinctive and important advance in the print media and image generation fields. Specific and detailed information concerning the novel print media materials of the invention and specialized fabrication methods associated therewith (which are equally unique) will be presented below in the following Summary of the Invention, Brief Description of the Drawings, and Detailed Description of Preferred Embodiments Sections.
It is an object of the present invention to provide highly efficient print media products for receiving inks, pigments, and other colorants thereon so that a printed image may be generated.
It is another object of the invention to provide highly efficient print media products which enable the generation of stable printed images thereon from a variety of different coloring agents in many divergent forms.
It is another object of the invention to provide highly efficient print media products which facilitate the generation of printed images that are light-fast and water-fast as defined above.
It is another object of the invention to provide highly efficient print media products wherein the printed images produced thereon may be generated using a wide variety of printing technologies including but not limited to those which employ thermal inkjet technology.
It is another object of the invention to provide highly efficient print media products which are able to retain printed images thereon that exhibit an excellent degree of stability over prolonged time periods and under conditions of varying temperature, humidity, and the like.
It is another object of the invention to provide highly efficient print media products wherein the printed images produced thereon are characterized by rapid drying times.
It is another object of the invention to provide highly efficient print media products wherein the overall level of gloss is readily controlled without major adjustments to the production process, with such process readily allowing the fabrication of high-gloss or semi-gloss products in an effective and economical manner.
It is another object of the invention to provide highly efficient print media products which are able to effectively accomplish all of the above-listed goals and others (including the generation of images that are substantially water-fast and highly-defined) in a simultaneous fashion, with this aspect of the invention being accomplished in accordance with the unique layering arrangements and chosen construction materials discussed herein.
It is a further object of the invention to provide highly efficient print media products which are able to effectively accomplish all of the above-listed goals using a minimal number of material layers and construction materials.
It is an even further object of the invention to provide highly efficient print media products which employ layering arrangements and construction materials that are readily suited to large scale mass-production fabrication processes in an economical fashion.
It is an even further object of the invention to provide highly efficient print media products that are readily used in a wide variety of different printing systems with differing inks for many diverse purposes.
It is a still further object of the invention to provide highly efficient, rapid, and economical manufacturing methods which may be employed to produce the print media products of the present invention as discussed herein.
Novel and effective print media products (also characterized herein as xe2x80x9cprint media sheetsxe2x80x9d, xe2x80x9cink-receiving sheetsxe2x80x9d, and the like) are described below which offer numerous advantages and benefits over prior structures. These benefits and advantages include, without limitation, the simultaneous achievement of items [1]-[9] recited above with particular reference to (A) light-fastness as previously defined; (C) the generation of highly defined and distinct images; and (D) a high degree of gloss-control as also defined above. In this regard, the claimed invention represents a significant advance in the print media technology and image generation fields.
As a preliminary point of information, the present invention shall not be restricted to any particular types, sizes, material-selections, arrangements of print media materials, components, chemical compositions, layering sequences, numbers of layers, layer orientations, thickness values, porosity parameters, and other related factors unless otherwise stated herein. Likewise, the numerical values listed in this section and the other sections provided below constitute preferred embodiments designed to provide optimum results and shall not limit the invention in any respect. In particular, it shall be understood that the specific embodiments discussed herein and illustrated in FIGS. 1-3 (along with the particular construction materials associated therewith) constitute special versions of the invention which, while non-limiting in nature, provide excellent results and are highly distinctive. All recitations of chemical formulae and structures set forth in the following discussion are intended to generally indicate the types of materials which may be used in this invention. The listing of specific chemical compositions which fall within the general formulae and classifications presented below are offered for example purposes only and shall be considered non-limiting.
The claimed invention and its novel developments are applicable to a wide variety of printing systems with particular reference to those that employ thermal inkjet technology as previously discussed. Likewise, a number of different ink materials can be used in connection with the invention without limitation, with the term xe2x80x9cink materialsxe2x80x9d being defined to encompass compositions incorporating dyes, pigments, and other colorants without restriction. In this regard, the claimed print media products shall not be considered xe2x80x9cink-specificxe2x80x9d or xe2x80x9cprinting method-specificxe2x80x9d in any fashion.
It should also be understood that the present invention shall not be limited to any particular construction techniques (including any given material deposition procedures, layering arrangements, and the like) unless otherwise stated below. For example, the terms xe2x80x9cformingxe2x80x9d, xe2x80x9capplyingxe2x80x9d, xe2x80x9cdeliveringxe2x80x9d, xe2x80x9cplacingxe2x80x9d, xe2x80x9cpositioningxe2x80x9d, xe2x80x9coperatively attachingxe2x80x9d, xe2x80x9coperatively connectingxe2x80x9d, xe2x80x9cconvertingxe2x80x9d, xe2x80x9cprovidingxe2x80x9d, and the like as used throughout this discussion and as claimed shall broadly encompass any appropriate manufacturing procedures including, without limitation, roll-coating, spray-coating, immersion-coating, cast-coating, and other related production methods. In this regard, the invention shall not be considered xe2x80x9cproduction method-specificxe2x80x9d unless otherwise stated herein, with the recitation of any particular fabrication techniques, layer deposition methods, number of layers being applied in a given step, and the like being set forth for example purposes only.
Likewise, it shall be understood that the terms xe2x80x9coperative connectionxe2x80x9d, xe2x80x9coperative attachmentxe2x80x9d, xe2x80x9cin operative connectionxe2x80x9d, xe2x80x9cin operative attachmentxe2x80x9d, xe2x80x9cpositioned onxe2x80x9d, xe2x80x9clocated onxe2x80x9d, xe2x80x9cpositioned abovexe2x80x9d, xe2x80x9cpositioned over and abovexe2x80x9d, xe2x80x9clocated over and abovexe2x80x9d, and the like as used and claimed herein shall be broadly construed to encompass a variety of divergent layering arrangements and assembly techniques. These arrangements and techniques include but are not limited to (1) the direct attachment of one material layer to another material layer with no intervening material layers therebetween; and (2) the attachment of one material layer to another material layer with one or more material layers therebetween provided that the one layer being xe2x80x9cattached toxe2x80x9d, xe2x80x9cconnected toxe2x80x9d, or xe2x80x9cpositioned over and abovexe2x80x9d, the other layer is somehow xe2x80x9csupportedxe2x80x9d by the other layer (notwithstanding the presence of one or more additional material layers therebetween). Use of the phrase xe2x80x9cdirect attachmentxe2x80x9d, xe2x80x9cdirectly attached onxe2x80x9d, xe2x80x9cdirectly attached toxe2x80x9d, xe2x80x9cdirectly positioned onxe2x80x9d, xe2x80x9cdirectly located onxe2x80x9d, and the like shall signify a situation wherein a given material layer is secured to another material layer without any intervening material layers therebetween. Any statement used herein which indicates that one layer of material is xe2x80x9cabovexe2x80x9d, xe2x80x9coverxe2x80x9d, or xe2x80x9con top ofxe2x80x9d another layer shall involve a situation wherein the particular layer that is xe2x80x9cabovexe2x80x9d, xe2x80x9coverxe2x80x9d, or xe2x80x9con top ofxe2x80x9d of the other layer in question shall be the outermost of the two layers relative to incoming ink materials being delivered by the printing system of interest. The opposite situation will be applicable regarding use of the terms xe2x80x9cbelowxe2x80x9d, xe2x80x9cunderxe2x80x9d, xe2x80x9cbeneathxe2x80x9d, xe2x80x9con the bottom ofxe2x80x9d, and the like. The characterizations recited above shall be effective regardless of the orientation of the print media materials under consideration.
Furthermore, any and all recitations of structures, layers, materials, and components in the singular throughout the claims, Summary of the Invention, and Detailed Description of Preferred Embodiments sections shall be construed to encompass a plurality of such items unless otherwise specifically noted herein.
As previously indicated, highly effective and versatile print media materials designed to receive ink materials thereon for the generation of clear, stable, and distinct printed images are provided. Many different ink delivery systems can be employed to generate the printed images of interest on the claimed media products without limitation although the use of devices that incorporate thermal inkjet technology are again preferred. Regardless of which ink delivery system is chosen, the present invention is capable of offering the considerable benefits listed above which include more efficient, rapid, and reliable image generation.
The following discussion shall constitute a brief and general overview of the invention which shall not limit the invention in any respect. More specific details concerning particular embodiments and other important features of the invention will again be recited in the Detailed Description of Preferred Embodiments section set forth below. All scientific terms used throughout this discussion shall be construed in accordance with the traditional meanings attributed thereto by individuals skilled in the art to which this invention pertains unless a special definition is provided herein.
As previously stated, the claimed invention involves one or more novel print media products (discussed in connection with a plurality of preferred embodiments) which are characterized by improved functional abilities, namely, more efficient image generation (e.g. excellent gloss-control/uniformity, rapid drying, image clarity, light-fastness, water-fastness, and the like which are all achieved in a simultaneous and automatic fashion). The components and novel features associated with the claimed print media products will now be briefly summarized.
In order to produce a preferred print media product in accordance with the invention, a support structure or xe2x80x9csubstratexe2x80x9d (with both terms being considered equivalent from a structural and functional standpoint) is initially provided on which the other layers associated with the print media product reside. Many different construction materials can be employed in connection with the substrate including those which are made from paper, plastics, or metals without limitation although paper (any commercially-available type) is preferred. The chosen substrate may be coated or uncoated on either or both sides thereof. In a preferred embodiment designed to provide optimum results, the substrate will include an upper surface (also characterized herein as a xe2x80x9cfirst sidexe2x80x9d) and a lower surface (also characterized herein as a xe2x80x9csecond sidexe2x80x9d), with at least one of such surfaces/sides (preferably the upper surface or both surfaces) being covered with a substantially non-porous, non-absorbent, and ink-impermeable composition in the form of a coating layer. A representative and exemplary coating composition associated with this embodiment involves polyethylene when a paper substrate is employed. However, other coating/substrate combinations can be employed without limitation, or the use of substrate coatings can be eliminated entirely if desired as determined by routine preliminary pilot testing.
Positioned (e.g. provided) over and above the substrate (and fixedly secured thereto with xe2x80x9cdirect attachmentxe2x80x9d of such layers as defined above being preferred but not necessarily required) is a xe2x80x9cmedial layerxe2x80x9d of material. From a functional standpoint, the medial layer is designed to provide a high degree of xe2x80x9ccapacityxe2x80x9d (e.g. ink-retention capability) in connection with the media product, to facilitate rapid drying of the printed, image-containing media product, to create a media product with a smooth/even surface, and to otherwise ensure that the desired gloss characteristics are maintained in the finished product. To accomplish these goals, the medial layer is optimally porous and generally non-swellable in the presence of liquids, with the term xe2x80x9cporousxe2x80x9d being basically defined in a conventional fashion to involve a structure or material having a plurality of pores therein through which fluids, etc. may pass. The transfer of fluids including ink and the like into and through the medial layer occurs via physical phenomena normally associated with porous materials including capillary action and the like. It should be noted that, if a substrate is employed which is coated (e.g. polyethylene-coated paper in a preferred embodiment), the medial layer and remaining layer(s) discussed below are optimally placed on the side or sides that are covered with the chosen coating formulation.
The primary ingredients used to fabricate the medial layer include at least one pigment and at least one binder although it shall be understood that various optional ingredients including fillers, surfactants, preservatives, and the like may also be combined therewith. The need for such other ingredients shall be determined by routine preliminary pilot testing. Nonetheless, the use of at least one pigment and binder without any other ingredients will function effectively in the present embodiment, although the addition of other ingredients as noted above is possible. A preferred pigment consists of silica (SiO2). Likewise, a representative and non-limiting silica material which may be employed in connection with the medial layer involves silica gel (discussed in greater detail below) having an exemplary and mean silica particle size value (e.g. diameter) of about 0.3-0.4 gm in water and mean porosity value of about 0.8-0.9 cc/g. However, other types of silica with differing particle size, porosity, and other parameters can be employed if needed and desired.
Combined with the above-mentioned pigment (preferably silica) is at least one binder (also referred to herein as a xe2x80x9cprimary binderxe2x80x9d) which is optimally of a water-soluble or water-dispersible organic polymer type. Regarding the binders used in the current embodiment and all other embodiments of the present invention, the term xe2x80x9cprimary bindersxe2x80x9d (or xe2x80x9cprimary binderxe2x80x9d) shall be used in connection with the binder materials employed in the medial layer while xe2x80x9csecondary bindersxe2x80x9d (or xe2x80x9csecondary binderxe2x80x9d) shall involve the binder compounds incorporated within the top layer (discussed below). A number of different primary binder materials alone or in combination can be employed within the medial layer. However, highly effective results are achieved through the use of polyvinyl alcohol as the sole primary binder in the medial layer. While the claimed invention shall not be restricted to any particular numerical quantities in connection with the chemical ingredients in the medial and other layers associated therewith, a preferred embodiment designed to provide best results will involve the use of a medial layer having the following pigment and primary binder quantities: about 67-87% by weight pigment (e.g. silica) with about 77% by weight being preferred, and about 13-33% by weight primary binder (e.g. polyvinyl alcohol) with about 23% by weight being preferred. It should be noted that, unless otherwise stated herein, all percentage figures describing the material content of the various layers discussed in the claims, Summary of the Invention, and Detailed Description of Preferred Embodiments sections shall involve xe2x80x9cdry weightxe2x80x9d, namely, the weight of the chosen component in the dried material layer of interest. Likewise, as previously stated, the claimed invention shall not be restricted to any given material quantities in connection with a given layer, with such quantities being subject to variation as needed and desired in accordance with routine preliminary testing. The preferred and non-limiting percentage figures recited herein for all of the ingredients employed in the various layers of this invention shall optimally represent values which reflect the total amount of the ingredient under consideration whether a single composition is employed or multiple compositions in combination are used. For example, the representative 23% by weight primary binder value recited above shall involve a situation where 23% by weight of a single binder may be employed or multiple binders in combination can be used which collectively constitute (as a total) 23% by weight of the dried media layer.
Next, positioned (e.g. provided) over and above the medial layer (and fixedly secured thereto with xe2x80x9cdirect attachmentxe2x80x9d of such layers as defined above being preferred but not necessarily required) is a xe2x80x9ctop layerxe2x80x9d of material. From a functional standpoint, the top layer is designed to provide a high-gloss character to the print media product and to likewise ensure the generation of clear and distinct images with high quality levels, rapid drying times, and a permanent/stable character. In this regard, the top layer is optimally high-gloss, non-porous, and generally swellable in the presence of liquids, with the term xe2x80x9cnon-porousxe2x80x9d being basically defined in a conventional fashion to involve a structure or material lacking a plurality of pores therein through which fluids, etc. may pass. The transfer of fluids including liquid ink and the like into and through the top layer occurs via physical phenomena normally associated with non-porous materials including non-capillary absorption and the like. While, in a preferred embodiment, the top layer shall be construed to involve the layer of material that is uppermost and the first layer to receive ink materials from the printer unit under consideration, it is contemplated in other embodiments that one or more additional layers/coatings may also be placed over and above the top layer without limitation. However, as outlined further below, the two-layer design discussed herein which employs the medial layer and top layer thereover (with the top layer being the first layer to receive ink materials) is particularly unique in terms of simplicity, functionality, and versatility.
The top layer in the present embodiment is particularly unusual in that it preferably involves a structure consisting essentially of one or more (e.g. at least one) binder materials (also characterized herein as xe2x80x9csecondary bindersxe2x80x9d). In accordance with the phrase xe2x80x9cconsisting essentially ofxe2x80x9d in the presently-described embodiment, the top layer will not contain therein any pigments or fillers (of a particulate or non-particulate nature) in more than negligible/trace quantities (for example, those quantities that would incidentally be present as a result of the manufacturing processes being employed). In other words, the top layer in the current embodiment will not include any pigments or fillers therein aside from minute, trace amounts that would be considered inconsequential. Likewise, as a general proposition, the top layer in this embodiment will not contain therein any composition(s) that would materially affect or alter the high-gloss character and/or non-porous nature of the top layer (for instance, to make it more porous or porous in general). In the present embodiment (which, while preferred and novel, shall not be considered the only embodiment in this case), it is therefore desired that the top layer be fabricated so that it is xe2x80x9cbinder-onlyxe2x80x9d from a material-content standpoint (e.g. optimally 100% by weight of one or more xe2x80x9csecondary binderxe2x80x9d materials). However, in accordance with the definitions listed above, it is possible that additional materials (namely, preservatives, surfactants, and others) may be added to the top layer as needed and desired provided that they again fit within the foregoing definitions.
In order to facilitate the goals of the top layer as outlined above in an especially effective manner, a plurality (e.g. two or more) of secondary binders are incorporated within the top layer, with each of the chosen secondary binders preferably being different and providing the completed top layer with multiple attributes. A number of different secondary binders alone or in combination may be used without limitation as discussed further below in the Detailed Description of Preferred Embodiments section. However, it has been discovered that unexpectedly effective results can be obtained through the use of three very special and distinctive secondary binder classes and materials in combination. Specifically, such classes (and a preferred composition within each class) are as follows: (1) Secondary Binder No. 1: a polyvinyl alcohol (particularly, acetoacetylated polyvinyl alcohol); (2) Secondary Binder No. 2: a polyurethane (particularly, at least one modified polyurethane resin dispersion); and (3) Secondary Binder No. 3: a polyamide resin (particularly, at least one epichlorohydrin-containing polyamide). Further information regarding these specific compounds, classes of materials, and other representative secondary binders will again be discussed below in the Detailed Description of Preferred Embodiments section. It should also be understood that, in a still further novel embodiment, the three specific secondary binders recited above, namely, a polyvinyl alcohol (particularly, acetoacetylated polyvinyl alcohol), a polyurethane (particularly, a modified polyurethane resin dispersion), and a polyamide resin (particularly, an epichlorohydrin-containing polyamide) could be employed in combination within the top layer along with other compositions such as pigments, fillers, and the like without restriction. However, the embodiment recited above which consists essentially of binders is again preferred.
All of the binders selected for use in the top layer preferably involve water-soluble or water-dispersible organic polymers. While the top layer shall not be restricted in connection with the types of secondary binders that are employed, the number of secondary binders being used, and/or the relative quantities of such binders, representative amounts of Secondary Binder Nos. 1-3 are as follows: about 74-94% by weight Secondary Binder No. 1 (e.g. a polyvinyl alcohol, optimally, acetoacetylated polyvinyl alcohol) with about 84% by weight being preferred, about 5-15% by weight Secondary Binder No. 2 (e.g. a polyurethane, optimally, a modified polyurethane resin dispersion) with about 10% by weight being preferred, and about 1-12% by weight Secondary Binder No. 3 (e.g. a polyamide resin, namely, an epichlorohydrin-containing polyamide) with about 6% by weight being preferred. It should again be noted and understood that, unless otherwise stated-herein, all percentage figures describing the material content of the various layers discussed in the claims, Summary of the Invention, and Detailed Description of Preferred Embodiments sections shall involve xe2x80x9cdry weightxe2x80x9d, namely, the weight of the chosen component in the dried material layer of interest. Likewise, the present invention shall again not be restricted to any given material quantities in connection with a particular layer or layers in the claimed print media products, with such quantities being subject to variation as needed and desired in accordance with routine preliminary testing. The preferred and non-limiting percentage figures recited herein for all of the ingredients employed in the various layers of this invention shall optimally represent values which reflect the total amount of the ingredient under consideration whether a single composition is employed or multiple compositions in combination are used.
The above-listed print media product represents a preferred embodiment of the current invention. As a point of general information, the-layers of materials associated with all of the embodiments expressed herein may be placed on one side (preferred) of the coated or uncoated substrate or on both sides without limitation. If a coated substrate is employed, it is particularly desirable to place the material layers on the coated side(s). Likewise, a number of different manufacturing techniques may be implemented in connection with this embodiment (and the other versions of the present invention) without restriction as outlined further below. However, from a general standpoint, the claimed method of interest regarding the above-listed embodiment will encompass the following basic steps (with the previously-described information involving construction materials and the like being incorporated by reference in the current discussion): (1) providing a substrate; (2) applying a medial layer in position over and above the substrate, with the medial layer being comprised of silica and at least one primary binder composition; and (3) placing a top layer over and above the medial layer, with the top layer consisting essentially of at least one secondary binder composition. Numerous variations are again possible in connection with the foregoing method which shall be encompassed within the claims provided below. One optional step which may be employed between steps (2) and (3) involves delivering a citric acid solution (e.g. about 0.7% by weight citric acid in a preferred and non-limiting embodiment) onto the surface of the medial layer prior to placement of the top layer in position thereover. It has been discovered that the use of this particular solution can assist in avoiding undesired bubble formation in the top layer, thereby ensuring that the top layer has a uniform consistency-which facilitates proper image formation thereon.
At least one or more additional embodiments of the present invention likewise exist with primary reference to a particular alternative print media sheet which will now be discussed. All of the information, materials, parameters, functional attributes, ingredient types, and other data concerning (1) the substrate; and (2) the medial layer as discussed above in connection with the first embodiment are applicable to the currently-described alternative embodiment unless otherwise stated herein and are therefore incorporated by reference in the present discussion. The main distinction between the first and second embodiments involves the material-content of the top layer which will now be described in detail. The top layers in both embodiments may, in fact, be the same from a secondary binder-standpoint, with all of the above-listed data regarding representative secondary binders, secondary binder types, secondary binder classes, etc. being applicable to the current embodiment and also incorporated herein by reference. However, in the embodiment presently being summarized, an additional ingredient is employed in combination with the secondary binder(s), namely, a small quantity of at least one (e.g. one or more) pigment. While the present invention shall not be restricted to any given pigment material or materials for this purpose, the use of silica is preferred (e.g. of the xe2x80x9cprecipitatedxe2x80x9d variety in an exemplary and non-limiting embodiment). This material is employed to create a xe2x80x9csatinxe2x80x9d-type, xe2x80x9csemi-glossxe2x80x9d top layer compared with the high-gloss character of the previous embodiment. To accomplish this goal, it is a novel feature of the second embodiment to employ a total pigment (e.g. silica) amount not more than about 10% by weight, namely, the dry weight of the dried top layer. This particular quantity value not only preserves and maintains the benefits provided by the secondary binder(s) from a non-porosity standpoint, but at the same time adds a semi-gloss, satin-type character to the top surface of the print media product. In particular, by carefully controlling the amount of pigment (e.g. silica) to not exceed about 10% by weight, the top layer can maintain its non-porous character which is desirable for the reasons given above while also exhibiting a semi-gloss, satin-type finish which is a distinctive combination of features. When employed in connection with a specialized medial layer containing a pigment (namely, silica) and a binder (preferably polyvinyl alcohol), the above-listed top layer creates a unique media sheet having multi-functional capabilities. It is especially important that these multiple capabilities are provided using only two material layers on the substrate. Accordingly, the second embodiment of the claimed invention likewise represents a significant advance in the art of print media technology from a structural and functional standpoint.
To quantitatively account for the pigment in the top layer of the current embodiment, it is preferred that the amount of secondary binder (or binders) be reduced. The claimed invention shall not be restricted to any particular secondary binder or binders that are decreased in quantity which may vary depending on the types of binders under consideration and whether multiple binders are employed. In a preferred version of the invention wherein the above-listed secondary binder compositions are used (e.g. Secondary Binder Nos. [1]-[3]), a representative and non-limiting embodiment will involve a reduction in the amount of the secondary binder which, in the absence of any pigments, would be present in the greatest quantity. In the current exemplary embodiment, this would involve Secondary Binder No. 1 as recited above (e.g. a polyvinyl alcohol, namely, acetoacetylated polyvinyl alcohol), with the reduction in this material equaling the amount of added pigment (e.g. silica). Thus, in the current non-limiting example which again represents an optimized version of the claimed invention, the following quantities would be employed: about 68-88% by weight Secondary Binder No. 1 (e.g. a polyvinyl alcohol, optimally, acetoacetylated polyvinyl alcohol) with about 78% by weight being preferred, about 5-15% by weight Secondary Binder No. 2 (e.g. a polyurethane, optimally, a modified polyurethane resin dispersion) with about 10% by weight being preferred, about 1-12% by weight Secondary Binder No. 3 (e.g. a polyamide resin, namely, an epichlorohydrin-containing polyamide) with about 6% by weight being preferred, and about 2-10% by weight pigment (e.g. silica) with about 6% by weight being preferred. Again, all of the percentage figures recited above represent dry weight (namely, the weight of the ingredient under consideration on a percentage basis as part of the overall dried top layer).
The numerical values listed herein shall not limit the invention in any respect and instead constitute preferred and optimized examples which are subject to modification as needed and desired. Regardless of the amounts and types of secondary binders that are employed within the top layer of the current embodiment, the addition of a pigment (namely, silica) in an amount not exceeding about 10% by weight will again serve to preserve the non-porous nature of the top layer which is desirable as previously noted, while likewise imparting a semi-gloss, satin-type finish to the completed print media product. The simultaneous provision of both features represents an important and unique concept which again constitutes a significant development in print media technology. As a further note concerning this alternative embodiment, additional materials (surfactants, preservatives, etc.) may likewise be employed within both the medial and top layers as needed and desired although, with reference to the top layer, it is preferred that no additional particulate or other compositions be employed therein including fillers, etc. (aside from the not more than 10% by weight pigment quantity and at least one secondary binder). Alternatively, if various other ingredients are added, it is preferred that they be of a type which would not materially affect or alter the semi-gloss character and/or non-porous nature of the top layer (for instance, to make it more porous or porous in general). In this regard, it is further preferred in a non-limiting fashion that the top layer in the current embodiment consist entirely or essentially of at least one secondary binder and not more than about 10% by weight pigment (e.g. silica).
A number of different manufacturing techniques may be employed in connection with the current alternative embodiment without restriction as outlined further below. However, from a general standpoint, the claimed method of interest regarding this embodiment will generally encompass the following steps (with the previously-described information involving construction materials and the like being incorporated by reference in the current discussion): (1) providing a substrate; (2) applying a medial layer in position over and above the substrate, with the medial layer being comprised of silica and at least one primary binder composition; and (3) placing a top layer over and above the medial layer, with the top layer being comprised of at least one secondary binder composition and silica, with the silica being present in an amount not exceeding about 10% by weight. Numerous variations are again possible in connection with the foregoing method which shall be encompassed within the claims provided below. One optional step which may, be employed between steps (2) and (3) involves delivering a citric acid solution (e.g. about 0.7% by weight citric acid in a preferred and non-limiting embodiment) onto the surface of the medial layer prior to placement of the top layer in position thereover. It has been discovered that the use of this particular solution can assist in avoiding undesired bubble formation in the top layer, thereby ensuring that the top layer has a uniform consistency which facilitates proper image formation thereon.